TWI853811B - Substrate processing apparatus - Google Patents

Abstract

There is provision of a substrate processing apparatus including an inner edge ring provided in a vicinity of a substrate to be placed on a stage in a processing chamber; a middle edge ring arranged outside the inner edge ring, the middle edge ring being configured to be moved vertically by an actuation mechanism; an outer edge ring arranged outside the middle edge ring; a first spring provided between the inner edge ring and the middle edge ring; and a second spring provided between the middle edge ring and the outer edge ring.

Description

Substrate processing equipment

The present invention relates to a substrate processing device.

In a plasma etching device, an edge ring is provided along the periphery of a wafer (for example, refer to Patent Document 1). The edge ring has the following functions: controlling the plasma near the periphery of the wafer and improving the uniformity of the etching rate within the surface of the wafer. [Known Technical Document] [Patent Document]

Patent document 1: Japanese Patent Application Publication No. 2008-244274

[The problem the invention is trying to solve]

The present invention provides a technology that can ensure thermal and electrical contact of the edge ring of the segmentation. [Technical means to solve the problem]

According to one aspect of the present invention, a substrate processing device is provided, comprising: an inner edge ring, disposed near a substrate placed on a platform in a processing chamber; a central edge ring, disposed outside the inner edge ring and movable up and down by a moving mechanism; an outer edge ring, disposed outside the central edge ring; a first spring, disposed between the inner edge ring and the central edge ring; and a second spring, disposed between the central edge ring and the outer edge ring. [Effects of the prior art]

According to one aspect of the present invention, thermal and electrical contacts of the separated edge rings can be ensured.

Hereinafter, the form for implementing the present invention will be described with reference to the drawings. In the specification and drawings of the present invention, for substantially the same configuration, the same symbols are given to omit repeated description.

[Substrate processing device] First, an example of the structure of a substrate processing device 5 according to an embodiment of the present invention will be described with reference to FIG1. FIG1 shows an example of the structure of a substrate processing device 5 according to an embodiment of the present invention. In the embodiment of the present invention, a capacitive coupling type parallel plate plasma processing device is used as an example of the substrate processing device 5 for description.

The substrate processing apparatus 5 includes, for example, a chamber 10 which is a cylindrical vacuum container made of metal such as aluminum or stainless steel. The chamber 10 is an example of a processing container, and its interior is a processing room for performing plasma processing. The chamber 10 is in a grounded state.

A disk-shaped platform 12 is disposed at the center of the bottom of the chamber 10 to place the wafer W, and is also used as a substrate holding table for the bottom electrode. The platform 12 is made of aluminum, for example, and is supported by a conductive cylindrical support 16 extending vertically upward from the bottom of the chamber 10 and a housing 100 disposed adjacent to the inside thereof.

An annular exhaust path 18 is formed between the conductive cylindrical support 16 and the inner wall of the chamber 10. An annular baffle 20 is installed at the top or the entrance of the exhaust path 18, and an exhaust port 22 is provided at the bottom of the exhaust path 18. In order to make the flow of gas in the chamber 10 axially symmetrical and uniform with respect to the wafer W on the platform 12, the following structure is preferably used: a plurality of exhaust ports 22 are provided at equal intervals in the circumferential direction.

The exhaust device 26 is connected to each exhaust port 22 through an exhaust pipe 24. The exhaust device 26 has a vacuum pump such as a turbomolecular pump, which can reduce the pressure of the plasma generation space S in the chamber 10 to a desired vacuum level. A gate valve 28 for opening and closing the wafer W loading and unloading port 27 is installed on the outer side of the side wall of the chamber 10.

The second RF power source 30 is electrically connected to the platform 12 through a matching device 32 and a power supply line 34. The second RF power source 30 can output a first frequency (e.g., 13.56 MHz, etc.) RF LF with variable power, which is suitable for controlling the energy of introducing ions into the wafer W. The matching device 32 is a matching circuit containing a variable reactance, and the matching circuit is used to match the impedance of the second RF power source 30 side with the impedance of the load (plasma, etc.) side.

An electrostatic chuck 36 for holding the wafer W by electrostatic adsorption is provided on the top surface of the platform 12. The electrostatic chuck 36 sandwiches an electrode 36a made of a conductive film between a pair of insulating films 36b, and the electrode 36a is electrically connected to a DC power source 40 through a switch 42 and a covered wire 43. The wafer W is electrostatically adsorbed and held on the electrostatic chuck 36 by the DC voltage supplied from the DC power source 40.

Inside the platform 12, for example, an annular coolant channel 44 extending in the circumferential direction is provided. A coolant of a predetermined temperature, such as cooling water cw, is circulated and supplied to the coolant channel 44 from the quench unit through pipes 46 and 48, and the temperature of the wafer W on the electrostatic chuck 36 can be controlled by the temperature of the coolant. In addition, a heater may also be provided inside the platform 12.

Furthermore, the heat transfer gas (e.g., He gas) from the heat transfer gas supply unit is supplied between the top surface of the electrostatic chuck 36 and the back surface of the wafer W through the gas supply pipe 50. Furthermore, in order to carry the wafer W in and out, the platform 12 is provided with a push pin and its lifting mechanism that penetrates the platform 12 in the vertical direction and can move up and down.

The shower head 51 disposed at the ceiling opening of the chamber 10 is installed to seal the opening of the ceiling of the chamber 10 by means of a shielding ring 54 covering its outer edge. The shower head 51 can also be formed of aluminum or silicon. The shower head 51 is used as a top electrode and faces the platform 12 which is also used as a bottom electrode.

A gas inlet 56 for introducing gas is formed in the shower head 51. A diffusion chamber 58 branching from the gas inlet 56 is provided inside the shower head 51. The gas output from the gas supply source 66 is supplied to the diffusion chamber 58 through the gas inlet 56 and diffused, and then introduced into the plasma generation space S from the plurality of gas supply holes 52.

The shower head 51 is electrically connected to the first RF power source 57 through a matching device 59 and a power supply line 60. The first RF power source 57 can output a second frequency (e.g., 40 MHz, etc.) of RF for plasma generation with variable power. The RF for plasma generation is a frequency suitable for plasma generation achieved by RF discharge and is higher than the first frequency. The matching device 59 is a matching circuit containing a variable reactance, and the matching circuit is used to match the impedance of the first RF power source 57 side with the impedance of the load (plasma, etc.) side.

The control unit 74 includes, for example, a microcomputer, and controls the operation of each unit in the substrate processing apparatus 5 and the operation of the entire apparatus. Examples of the units in the substrate processing apparatus 5 include: an exhaust device 26, a first RF power source 57, a second RF power source 30, a matching device 32, a matching device 59, a switch 42 for an electrostatic chuck, a gas supply source 66, a quencher unit, and a heat transfer gas supply unit.

In the substrate processing device 5, in order to perform various processes such as etching, the gate valve 28 is first opened and the wafer W is loaded into the chamber 10 from the loading and unloading port 27 and placed on the electrostatic chuck 36. Then, after the gate valve 28 is closed, a predetermined gas is introduced into the chamber 10 from the gas supply source 66 at a predetermined flow rate and flow rate ratio, and the pressure in the chamber 10 is reduced to a predetermined set value by the exhaust device 26. Furthermore, the first RF power source 57 is turned on to output the RF HF for plasma generation at a predetermined power, and is supplied to the shower head 51 through the matching device 59 and the power supply line 60.

On the other hand, when applying the radio frequency LF for ion introduction control, the second radio frequency power source 30 is turned on to output the radio frequency LF at a predetermined power, and applied to the stage 12 via the matching device 32 and the power supply line 34. Moreover, while the heat transfer gas is supplied from the heat transfer gas supply unit to the contact surface between the electrostatic chuck 36 and the wafer W, the switch 42 is turned on to apply the DC voltage from the DC power source 40 to the electrode 36a of the electrostatic chuck 36, and the heat transfer gas is confined to the above-mentioned contact surface by the electrostatic adsorption force.

[Edge ring divided into three parts] An edge ring 38 is provided on the outer periphery of the platform 12 and near the wafer W to surround the outer edge of the wafer W in a ring shape. The function of the edge ring 38 is to control the plasma on the outer periphery of the wafer W and improve the uniformity of the processing such as the etching rate within the surface of the wafer W.

The edge ring 38 is divided into three parts, including an inner edge ring 38i, a central edge ring 38m and an outer edge ring 38o. The inner edge ring 38i is disposed near the wafer W placed on the platform 12 in the processing chamber. The central edge ring 38m is disposed outside the inner edge ring 38i and can be moved up and down by the moving mechanism 200. The outer edge ring 38o is disposed outside the central edge ring 38m.

The moving mechanism 200 has a lifting pin 102. The lifting pin 102 moves up and down by the power generated by the piezoelectric actuator 101 through the component 104 (104a) and the bearing part 105. Thereby, the connecting part 103 moves up and down, and correspondingly, the central edge ring 38m connected to the connecting part 103 also moves up and down.

(Structure of edge ring) Next, the structure of edge ring 38 and its periphery is described in detail with reference to Fig. 2 and Fig. 3. Also, the up and down movement of the central edge ring 38m is described with reference to Fig. 4.

Fig. 2 is a diagram showing an example of an enlarged longitudinal section of the edge ring 38 and its periphery. In Fig. 2, the edge ring 38, the moving mechanism 200 and the piezoelectric actuator 101 according to the embodiment of the present invention are shown.

FIG3(a) is a three-dimensional view of each part of the edge ring 38 divided into three parts, FIG3(b) is a top view of each part of the edge ring 38 divided into three parts, FIG3(c) is a cross-sectional view taken along the A-A line of FIG3(b), and FIG3(d) is a cross-sectional view taken along the B-B line of FIG3(b).

As shown in FIG. 2 and FIG. 3 , the inner edge ring 38i is a member disposed near the outer periphery of the wafer W and surrounds the wafer W from below, and is the innermost member of the edge ring 38. The central edge ring 38m is a member disposed outside the inner edge ring 38i and surrounds the inner edge ring 38i. The outer edge ring 38o is a member disposed outside the central edge ring 38m and is the outermost member of the edge ring 38. The inner edge ring 38i and the outer edge ring 38o are fixed to the top surface of the electrostatic chuck 36 via the heat transfer sheet 39i and the heat transfer sheet 39o. The central edge ring 38m can be moved up and down by the moving mechanism 200.

As shown in Fig. 3 (a) and (b), the central edge ring 38m includes: an annular portion 38m1 surrounding the periphery of the wafer W, and three convex portions 38m2. The convex portions 38m2 are rectangular components that are evenly spaced and arranged on the outer peripheral side of the annular portion 38m1 and protrude from the outer peripheral side of the annular portion 38m1. As shown in Fig. 2, the longitudinal section of the annular portion 38m1 is L-shaped. If the central edge ring 38m is pushed upward, the L-shaped step portion of the annular portion 38m1 will change from a state of contact with the step portion of the inner edge ring 38i having an L-shaped longitudinal section to a state of separation.

(Moving mechanism and driving part) The protruding piece 38m2 of the central edge ring 38m is connected to the annular connecting part 103. The connecting part 103 moves up and down inside the space 16a provided in the conductive cylindrical supporting part 16.

The moving mechanism 200 is a mechanism for moving the central edge ring 38m up and down. The moving mechanism 200 includes: a lifting pin 102 and a bearing 105. The moving mechanism 200 is installed on the housing 100 arranged around the platform 12, and can move up and down by the power of the piezoelectric actuator 101 installed on the housing 100. The lifting pin 102 can also be formed of sapphire.

The housing 100 is formed of an insulating material such as alumina. The side and bottom of the housing 100 are disposed adjacent to the conductive cylindrical support portion 16 inside the conductive cylindrical support portion 16. A recess 100a is formed on the lower side of the interior of the housing 100. A moving mechanism 200 is disposed inside the housing 100. The lifting pin 102 passes through the housing 100 and the platform 12, and contacts the bottom surface of the connecting portion 103 in the space 16a provided in the conductive cylindrical support portion 16. The bearing portion 105 is engaged with a component 104a provided inside the housing 100. An O-ring 111 is provided in the pin hole of the lifting pin 102 for separating the vacuum space from the atmospheric space.

The lower end of the lifting pin 102 is inserted from above into the recess 105a at the front end of the bearing part 105. If the bearing part 105 is positioned by the piezoelectric actuator 101 and moves up and down through the component 104a, the lifting pin 102 will also move up and down, pushing up or pressing down the bottom surface of the connecting part 103. Thereby, the central edge ring 38m will move up and down through the connecting part 103.

The upper end of the piezoelectric actuator 101 is fixed to the component 104a by a screw 104c, and the lower end of the piezoelectric actuator 101 is fixed to the component 104b by a screw 104d. Thus, the piezoelectric actuator 101 is fixed in the housing 100 between the components 104a and 104b.

The piezoelectric actuator 101 is a positioning element that uses the piezoelectric effect and can be positioned with a resolution of 0.006mm (6μm). The lifting pin 102 moves up and down according to the displacement of the piezoelectric actuator 101 in the up and down direction. In this way, the central edge ring 38m can move a predetermined height with 0.006mm as the minimum unit.

The lifting pin 102 is provided to correspond to the "protruding piece portion 38m2 provided at three positions at equal intervals in the circumferential direction of the central edge ring 38m shown in Fig. 3 (a) and (b)". With this configuration, the lifting pin 102 pushes the central edge ring 38m upward from three positions through the annular connecting portion 103 and pushes it upward to a predetermined height.

A recess 138 having a width wider than the protruding piece 38m2 is formed on the bottom surface of the outer edge ring 38o and at the top of the protruding piece 38m2 of the central edge ring 38m. When the central edge ring 38m is pushed upward by the lifting pin 102 and moved to the uppermost position, the protruding piece 38m2 is accommodated in the recess 138. In this way, the central edge ring 38m can be pushed upward while the outer edge ring 38o is fixed.

FIG3(d) showing the cross section along the line B-B of FIG3(b) shows a state where the annular connecting portion 103 is pushed upward in the space 16a of the conductive cylindrical supporting portion 16 due to the upward movement of the lifting pin 102 when the space of the recess 138 and the lifting pin 102 do not exist.

Returning to FIG. 2 , the piezoelectric actuator 101 is disposed in the inner space of the housing 100 below the lift pin 102 in a one-to-one manner with the lift pin 102. That is, the three moving mechanisms 200 and the piezoelectric actuator 101 correspond to the lift pins 102 at three positions in a one-to-one manner and are disposed inside the housing 100. The components 104a and 104b are annular components, and the three piezoelectric actuators 101 are connected to each other by being fixed to the upper and lower components 104a and 104b by screws. In addition, the piezoelectric actuator 101 according to the embodiment of the present invention is an example of a driving unit.

As described above, in this configuration, the platform 12 and the electrostatic chuck 36 are supported by the housing 100, and the moving mechanism 200 and the driving part are mounted on the housing 100. Thus, without changing the design of the electrostatic chuck 36, the current electrostatic chuck 36 can be used and only the central edge ring 38m can be moved up and down.

As shown in FIG. 2 , in the embodiment of the present invention, a predetermined space is provided between the top surface of the electrostatic chuck 36 and the bottom surface of the central edge ring 38m, so that the central edge ring 38m can be moved not only upward but also downward. Thus, the central edge ring 38m can be moved not only upward but also downward by a predetermined height within the predetermined space. By moving the central edge ring 38m not only upward but also downward, the control range of the sheath can be expanded.

However, the driving unit is not limited to the piezoelectric actuator 101, and a motor capable of positioning control with a resolution of 0.006 mm may also be used. In addition, the driving unit may be one or more. Furthermore, the driving unit may also share a motor that moves the push pin that pushes up the wafer W up and down. In this case, a mechanism is required that can use gears and a power switching unit to switch and transmit the power of the motor between the "push pin for wafer W" and the "lifting pin 102 for the central edge ring 38m", and a mechanism that can control the up and down movement of the lifting pin 102 with a resolution of 0.006 mm. However, since the diameter of the central edge ring 38m disposed on the outer periphery of the 300mm wafer W is as large as about 310mm, it is better to provide a driving unit on each lifting pin 102 as in the embodiment of the present invention.

The control unit 74 can also control the positioning of the piezoelectric actuator 101 so that the displacement of the piezoelectric actuator 101 in the vertical direction becomes an amount corresponding to the wear amount of the central edge ring 38m. The control unit 74 can also set the displacement of the piezoelectric actuator 101 in the vertical direction according to the process conditions, which is independent of the wear amount of the central edge ring 38m.

If the top surface of the wafer W and the edge ring 38 are at the same height, the sheath on the wafer W during etching can be made the same height as the sheath on the edge ring 38. Then, by making the height of the sheath the same, the uniformity of the etching rate in the entire surface of the wafer W can be improved.

When the edge ring 38 is new, the sheath layer on the wafer W being etched is at the same height (flat) as the sheath layer on the edge ring 38, so the etching rate of the entire surface of the wafer W is uniform. At this time, as shown in FIG. 4(a-1), the central edge ring 38m is not pushed up by the lifting pin 102 (0mm). In addition, FIG. 4(a-1) shows the state of the A-A line section of FIG. 3(b), and FIG. 4(b-1) shows the state of the corresponding B-B line section of FIG. 3(b).

Next, if the edge ring 38 is worn out due to plasma processing such as etching, the sheath height of the edge ring 38 will become lower than the sheath height of the wafer W. As a result, the etching rate at the edge of the wafer W will increase, or the etched shape will be tilted. The so-called tilting of the etched shape means that the sheath at the edge of the wafer W becomes tilted due to the wear of the edge ring, causing ions to be introduced into the wafer W from the tilted direction, thereby causing the etched shape to become tilted instead of vertical. In the embodiment of the present invention, the edge of the wafer W refers to an annular portion 140 mm to 150 mm away from the center of the wafer W in the radial direction.

Furthermore, in the embodiment of the present invention, the central edge ring 38m is pushed upward only by the amount consumed by the edge ring 38, so that the height of the wafer W and the sheath layer on the edge ring 38 are consistent. This can prevent the etching rate of the edge of the wafer W from jumping or the etching shape from tilting.

For example, if the wear amount of the edge ring 38 is 1.0 mm, the control unit 74 can also position the piezoelectric actuator 101 to move the central edge ring 38m upward by 1.0 mm. As a result, as shown in FIG. 4 (a-2) and (b-2), the central edge ring 38m moves upward by 1.0 mm.

[Contact structure of the central edge ring] In the edge ring 38 of this structure, the inner edge ring 38i and the outer edge ring 38o are in contact with and fixed to the electrostatic chuck 36 via the heat transfer sheet 39i and the heat transfer sheet 39o. Therefore, the inner edge ring 38i and the outer edge ring 38o, which are non-movable parts, are in a thermally and electrically stable state.

In contrast, since the central edge ring 38m can move up and down, it is in a thermally unstable and electrically unstable state, which may affect the temperature controllability of the central edge ring 38m. If the temperature controllability of the central edge ring 38m deteriorates, it will become difficult to control the edge of the wafer W, especially in the deposition process, and the process characteristics between the wafers W in the batch will vary, resulting in poor productivity. In addition, in the edge ring 38 according to one embodiment of the present invention described below, a contact method is proposed to make the movable central edge ring 38m in a thermally stable and electrically stable state.

>Example 1> First, the structure of the edge ring 38 in Example 1 according to one embodiment of the present invention is described with reference to FIG5. The edge ring 38 of Example 1 includes: a contact member 37a provided between the inner edge ring 38i and the central edge ring 38m, and a contact member 37b provided between the central edge ring 38m and the outer edge ring 38o.

The contact member 37a is a horizontal surface provided between the inner edge ring 38i and the central edge ring 38m. The contact member 37b is a horizontal surface provided between the central edge ring 38m and the outer edge ring 38o.

Fig. 5 (a-1) and (a-2) show the A-A line section of Fig. 3 (b). In Fig. 5 (a-1), the central edge ring 38m is not pushed up by the lifting pin 102, that is, it is in a down state (0mm). In Fig. 5 (a-2), the central edge ring 38m is pushed up by the lifting pin 102, that is, it is in an up state (1mm, for example).

Fig. 5 (b-1) and (b-2) show the B-B line section of Fig. 3 (b). In Fig. 5 (b-1), the central edge ring 38m is not pushed up by the lifting pin 102, that is, it is in the down state. In Fig. 5 (b-2), the central edge ring 38m is pushed up by the lifting pin 102, that is, it is in the up state. The moving mechanism 200 can push the central edge ring 38m up by a predetermined amount with a resolution of 0.006mm.

In the down state where the central edge ring 38m is not pushed up by the lifting pin 102 as shown in Fig. 5 (a-1) and (b-1), the contact member 37a is displaced by being pressed on the horizontal surface between the inner edge ring 38i and the central edge ring 38m. As a result, the contact area between the contact member 37a and the inner edge ring 38i and the central edge ring 38m is enlarged, thereby increasing the thermal and electrical contact of the central edge ring 38m.

On the other hand, the contact member 37b is pressed weakly on the horizontal surface between the central edge ring 38m and the outer edge ring 38o, so the displacement is small. However, since the contact member 37b is clamped, the thermal and electrical contact between the central edge ring 38m and the electrostatic chuck 36 across the outer edge ring 38o can be stably ensured.

In the up state of the central edge ring 38m as shown in Fig. 5 (a-2) and (b-2) being pushed upward by the lifting pin 102, the contact member 37b is pressed and displaced between the central edge ring 38m and the outer edge ring 38o. As a result, the contact area between the contact member 37b and the central edge ring 38m and the outer edge ring 38o becomes larger, thereby increasing the thermal contact and electrical contact of the central edge ring 38m.

On the other hand, the contact member 37a is pressed weakly on the horizontal surface between the inner edge ring 38i and the central edge ring 38m, so the displacement is small. However, since the contact member 37a is clamped, the thermal and electrical contact between the central edge ring 38m and the electrostatic chuck 36 across the inner edge ring 38i can be stably ensured.

In the first embodiment, the contact members 37a and 37b are arranged all around the circumference, so that the movable central edge ring 38m can stably contact the immovable inner edge ring 38i and outer edge ring 38o. In this way, the heat transfer between the platform 12 and the central edge ring 38m can be improved, and the temperature controllability of the edge ring 38 is improved. In this way, the edge of the wafer W can be well controlled, and the deviation of the process characteristics between the wafers W in a batch can be eliminated, thereby improving the productivity.

In addition, the convex piece 38m2 is prone to buckling, so it may be difficult to control the central edge ring 38m at the intended position with high accuracy due to the buckling. However, by suppressing the buckling of the convex piece 38m2 through the contact members 37a and 37b, the central edge ring 38m can be positioned more accurately.

Furthermore, under the process conditions of applying high-power radio frequency power, abnormal discharge caused by the electrical floating of the central edge ring 38m can be suppressed, thereby reducing the risk of damage to the edge ring 38.

The contact members 37a and 37b may also be arranged in the circumferential direction, but not on the entire circumference. However, in order to stably make the central edge ring 38m contact the platform 12, the contact members 37a and 37b are preferably arranged on the entire circumference in the circumferential direction.

The contact member 37a described in the first embodiment is an example of a first spring provided between the inner edge ring 38i and the central edge ring 38m. The contact member 37b described in the first embodiment is an example of a second spring provided between the central edge ring 38m and the outer edge ring 38o.

>Example 2> Next, the structure of the edge ring 38 in Example 2 according to one embodiment of the present invention is described with reference to FIG. 6. The edge ring 38 of Example 2 includes: a contact member 37a disposed between the platform 12 and the central edge ring 38m, and a contact member 37b disposed between the central edge ring 38m and the outer edge ring 38o.

The contact member 37a is provided on a horizontal surface between the platform 12 and the central edge ring 38m. The contact member 37b is provided on a horizontal surface between the central edge ring 38m and the outer edge ring 38o.

Fig. 6 (a-1) and (a-2) show the A-A line section of Fig. 3 (b). In Fig. 6 (a-1), the central edge ring 38m is not pushed up by the lifting pin 102, that is, it is in a down state (0mm). In Fig. 6 (a-2), the central edge ring 38m is pushed up by the lifting pin 102, that is, it is in an up state (1mm, for example).

Fig. 6 (b-1) and (b-2) show the B-B line section of Fig. 3 (b). In Fig. 6 (b-1), the central edge ring 38m is not pushed up by the lifting pin 102, that is, it is in the down state. In Fig. 6 (b-2), the central edge ring 38m is pushed up by the lifting pin 102, that is, it is in the up state.

In the down state of the central edge ring 38m shown in Fig. 6 (a-1) and (b-1) and not pushed up by the lifting pin 102, the contact member 37a is pressed and displaced on the horizontal surface between the electrostatic chuck 362 and the central edge ring 38m. As a result, the contact area between the contact member 37a, the electrostatic chuck 362 and the central edge ring 38m is enlarged, thereby increasing the thermal contact and electrical contact of the central edge ring 38m.

On the other hand, the contact member 37b is pressed weakly on the horizontal surface between the central edge ring 38m and the outer edge ring 38o, so the displacement is small. However, since the contact member 37b is clamped, the thermal and electrical contact between the central edge ring 38m and the electrostatic chuck 36 across the outer edge ring 38o can be stably ensured.

In the up state of the central edge ring 38m as shown in Fig. 6 (a-2) and (b-2) being pushed upward by the lifting pin 102, the contact member 37b is pressed and displaced between the central edge ring 38m and the outer edge ring 38o. As a result, the contact area between the contact member 37b and the central edge ring 38m and the outer edge ring 38o is enlarged, thereby ensuring thermal and electrical contact of the central edge ring 38m.

On the other hand, the contact member 37a is pressed weakly on the horizontal surface between the inner edge ring 38i and the central edge ring 38m, so the displacement is small. However, since the contact member 37a is sandwiched, the thermal and electrical contact between the platform 12 and the central edge ring 38m can be stably ensured.

As can be seen from the above, in Embodiment 2, the movable central edge ring 38m can be stably contacted with the platform 12 through the non-movable inner edge ring 38i and the outer edge ring 38o by the contact members 37a and 37b provided on the protruding piece portion 38m2. In this way, the temperature controllability of the edge ring 38 can be improved, the edge of the wafer W can be well controlled, and the deviation of the process characteristics between the wafers W in a batch can be eliminated, thereby improving the productivity.

In addition, in Embodiment 2, the thermal and electrical contacts between the platform 12 and the central edge ring 38m are ensured by the contact members 37a and 37b. Therefore, under the process conditions of applying high-power RF power, the abnormal discharge caused by the electrical floating of the central edge ring 38m can be suppressed, so that the damage risk of the edge ring 38 is reduced.

In the second embodiment, the contact members 37a and 37b are provided in the circumferential direction. Specifically, the contact members 37a and 37b are provided in the convex piece portion 38m2 at three positions in the circumferential direction. Furthermore, the contact member 37a described in the second embodiment is an example of a first spring provided between the platform 12 and the central edge ring 38m. The contact member 37b described in the second embodiment is an example of a second spring provided between the central edge ring 38m and the outer edge ring 38o.

[Features of contact members] The contact members 37a and 37b of embodiments 1 and 2 shown in FIG. 5 and FIG. 6 may also have the following features. First, the contact members 37a and 37b of embodiments 1 and 2 are elastic members, preferably in the form of a coil. The contact members 37a and 37b are preferably inclined coils. For example, the contact members 37a and 37b may also be inclined coil springs wound obliquely into a coil shape. The contact members 37a and 37b may also be arranged with coils obliquely in the circumferential direction. The contact members 37a and 37b are preferably arranged on the entire circumference in the circumferential direction. The contact members 37a and 37b may also be formed of any one of benzene copper (BeCu), tungsten (W) or tantalum (Ta).

Thus, the central edge ring 38m of the movable part can be in a state of stable contact with the platform 12, rather than being in a state of thermal floating and electrical floating. Thus, the temperature controllability of the edge ring 38 as a whole can be improved, and the generation of abnormal discharge can be prevented.

In the first and second embodiments, the contact members 37a and 37b are arranged on the horizontal surface of the central edge ring 38m, but the present invention is not limited thereto. For example, a recess may be formed on the vertical surface of the recess 138 of the outer edge ring 38o into which the convex piece 38m2 of the central edge ring 38m is inserted, and the contact member 37b may be buried in the recess. In this case, the contact member 37b is arranged on the vertical surface of the central edge ring 38m and the outer edge ring 38o. In this way, the contact between the central edge ring 38m and the outer edge ring 38o can be stably maintained.

Compared to using a wider elastic member with a larger "region where the change in the rebound force relative to the displacement is large", the contact members 37a and 37b are preferably elastic members with a wider "region where the change in the rebound force relative to the displacement is small". For example, the contact members 37a and 37b may also be elastic members having the following characteristics: the region where the "load change of the spring itself" corresponding to the "displacement generated by the external force" is below the critical value is above a specific ratio relative to the maximum displacement.

FIG7 is a diagram showing an example of load variation of a spring, where the horizontal axis represents the displacement of the spring and the vertical axis represents the rebound force of the spring. Spring C is an example of an elastic member having a wider region where the rebound force of the spring relative to the displacement varies more. Spring D is an example of an elastic member having a wider region where the rebound force of the spring relative to the displacement varies less.

For example, as shown in the graph of FIG. 7( a ), if the maximum displacement of the spring is set to Dm and the specific ratio is set to 70%, the area Db where the change of the rebound force relative to the displacement of the spring C is within the range of the critical value P is below the specific ratio (here 70%) relative to the maximum displacement Dm. Therefore, the spring C is an elastic member with a relatively wide "area where the change of the rebound force relative to the displacement is relatively large", and does not have suitable characteristics for use as the contact members 37a, 37b.

On the other hand, the spring D has a region Da in which the change in the rebound force relative to the displacement is greater than 70% relative to the maximum displacement Dm within the critical value P. Therefore, the spring D is an elastic member having a relatively wide "region in which the change in the rebound force relative to the displacement is relatively small", and has suitable characteristics for use as the contact members 37a, 37b.

When driving the "motor that moves the moving mechanism 200", the rebound force of the springs of the two contact members 37a and 37b is preferably smaller. If the rebound force of the spring is larger, it will be difficult to drive the motor smoothly.

In the graph of FIG. 7( b ), the spring characteristics when two springs D1 and D2 having the same characteristics as the spring D are combined (that is, when the springs D1 and D2 are used as the contact members 37 a and 37 b ) are shown as the spring D12 .

In contrast, the spring characteristic obtained when two springs C1 and C2 having the same characteristics as the spring C are combined (that is, when the springs C1 and C2 are used as the contact members 37a and 37b) is shown as spring C12.

The spring D12 is a spring in which the area where the change in the rebound force relative to the displacement is small is wider. According to the above, since the area where the change in the rebound force relative to the displacement is small is wider, the load applied to the edge ring 38 is smaller. For example, as long as it is within a specific range derived in advance from the characteristics of the spring D12, even if the displacement changes, the rebound force remains almost unchanged. Due to the characteristics of this spring D12, by using "contact members 37a, 37b whose rebound force is fixed regardless of the central edge ring 38m being raised or lowered to any position", the piezoelectric actuator 101, motor and other actuators that move the moving mechanism 200 can be stably driven. Thereby, the central edge ring 38m can be controlled more accurately at a predetermined position. In addition, the spring C12 has a relatively large rebound force, so it is difficult to improve the lifting accuracy of the central edge ring 38m.

FIG8 is a diagram for explaining the contact resistance of the contact members 37a and 37b according to an embodiment of the present invention. FIG8(a) shows the contact resistance of the plate springs 137a and 137b in the case of using the plate springs 137a and 137b as a comparative example. FIG8(b) shows the contact resistance of the contact members 37a and 37b in the case of using the inclined coil spring as an example of the contact members 37a and 37b according to an embodiment of the present invention. In each figure, the states of "balance" and "when the center edge ring 38m is lowered" are shown.

In the "balanced" state in the comparison example of FIG. 8 (a-1), the leaf springs 137a and 137b are respectively disposed between the inner edge ring 38i and the central edge ring 38m, and between the central edge ring 38m and the outer edge ring 38o, and maintain a balanced state.

In contrast, when the central edge ring 38m of FIG. 8(a-2) is lowered, the plate spring 137a is pressed from above, thereby increasing the contact area between the plate spring 137a and the inner edge ring 38i and the central edge ring 38m. As a result, the contact resistance (thermal resistance) of the inner edge ring 38i and the central edge ring 38m is reduced, thereby improving heat conduction. On the other hand, the contact between the outer edge ring 38o and the central edge ring 38m can be ensured by the plate spring 137b.

In the case of springs such as the leaf springs 137a and 137b, "the region where the spring's rebound force is larger relative to the displacement is wider", the "load variation on the drive part such as the motor" relative to the displacement is larger because the spring's rebound force is larger relative to the displacement. Therefore, it is difficult to smoothly operate the drive part.

In the embodiment of the present invention, a spring having a wider area where the spring has a smaller rebound force relative to the displacement is used for the contact members 37a and 37b. For example, if the contact members 37a and 37b are inclined coil springs, in the "balanced state" of the embodiment of the present invention in FIG. 8 (b-1), the contact members 37a and 37b are respectively arranged between the inner edge ring 38i and the central edge ring 38m, and between the central edge ring 38m and the outer edge ring 38o, and maintain a balanced state.

When the central edge ring 38m of FIG8(b-2) is lowered, the contact member 37a of the tilted coil spring is pressed from above, thereby increasing the contact area between the inner edge ring 38i and the central edge ring 38m. As a result, the contact resistance (thermal resistance) of the inner edge ring 38i and the central edge ring 38m is reduced, thereby improving heat conduction. On the other hand, the contact between the outer edge ring 38o and the central edge ring 38m can be ensured by the contact member 37b.

In a spring having a wider "region where the spring's rebound force relative to the displacement is smaller" such as the contact members 37a and 37b of the inclined coil spring, the rebound force relative to the displacement is smaller, so the "load change on the drive part such as the motor" relative to the displacement is smaller. Therefore, it is easy to smoothly operate the drive part.

That is, as shown in FIG. 7( b ), the contact pressure of the contact members 37a and 37b of the inclined coil spring according to one embodiment of the present invention does not change significantly within a range that is appropriate both up and down, so the displacement of the thermal resistance is small. Therefore, the central edge ring 38m of the movable part can be stably in thermal and electrical contact with the platform 12 through the inner edge ring 38i and the outer edge ring 38o of the non-movable part.

In the above, the leaf spring is cited as an elastic member having a larger area in which the change of the spring's rebound force relative to the displacement is larger, but the leaf spring having the following characteristics is not included: the area in which the change of the spring's rebound force relative to the displacement is smaller is larger. In addition, the spring member having a larger area in which the change of the spring's rebound force relative to the displacement is smaller is not limited to the inclined coil spring. For example, any elastic member having the following characteristics can be used as the contact members 37a, 37b according to one embodiment of the present invention: the load variation of the spring corresponding to the displacement is in a region below a critical value and is above a specific ratio relative to the maximum displacement.

As described above, according to the substrate processing apparatus 5 of the embodiment of the present invention, the movable central edge ring 38m can stably make electrical and thermal contact with the platform 12. Thus, the temperature controllability of the edge ring 38 can be improved, so that the edge of the wafer W can be well controlled, and the deviation of the process characteristics between the wafers W in a batch can be eliminated, so that the productivity can be improved.

Furthermore, by stably bringing the central edge ring 38m into electrical and thermal contact with the platform 12, abnormal discharge can be suppressed and the risk of damage to the edge ring 38 can be reduced.

It should be understood that the substrate processing device disclosed in this disclosure is for illustration only and is not intended to be limiting. The above-mentioned one embodiment of the present invention can be modified and improved in various forms without departing from the scope and subject matter of the attached patent application. The matters described in the above-mentioned multiple embodiments can also be configured in other ways within the scope of non-contradiction, and can be combined within the scope of non-contradiction.

The substrate processing apparatus of the present invention may also be applicable to any of the following types: Capacitively Coupled Plasma (CCP), Inductively Coupled Plasma (ICP), Radial Line Slot Antenna, Electron Cyclotron Resonance Plasma (ECR), Helicon Wave Plasma (HWP).

In this specification, wafer W is cited as an example of a substrate for explanation. However, the substrate is not limited thereto, and may be various substrates used for LCD (Liquid Crystal Display), FPD (Flat Panel Display), CD substrate, printed substrate, etc.

5. Substrate processing device 10. Chamber 12. Platform 16. Conductive cylindrical support 16a, S. Space 18. Exhaust path 20. Baffle 22. Exhaust port 24. Exhaust pipe 26. Exhaust device 28. Gate valve 30. Second RF power supply 32. Matching device 34. Power supply line 36. 362. Electrostatic chuck 36a. Electrode 36b‧‧‧Insulating film 37a, 37b‧‧‧Contact member 38‧‧‧Edge ring 38i‧‧‧Inner edge ring 38m‧‧‧Center edge ring 38m1‧‧‧Annular part 38m2‧‧‧Tubular part 38o‧‧‧Outer edge ring 39i, 39o‧‧‧Heat transfer sheet 40‧‧‧DC power supply 42‧‧‧Switch 43‧‧‧Sheathed wire 44‧‧‧Refrigerant channel 46, 48‧‧‧Pipe 50‧‧‧Gas Gas supply pipe 51‧‧‧Sprinkler head 52‧‧‧Gas supply hole 54‧‧‧Shielding ring 56‧‧‧Gas inlet 57‧‧‧First RF power supply 58‧‧‧Diffusion chamber 59‧‧‧Matching device 60‧‧‧Power supply line 66‧‧‧Gas supply source 74‧‧‧Control unit 100‧‧‧Casing 100a, 105a, 138‧‧‧Concave 101‧‧‧Piezoelectric actuator 102‧‧‧Lifting pin 103‧‧‧ Connecting part 104, 104a, 104b‧‧‧Component 104c, 104d‧‧‧Screw 105‧‧‧Bearing part 111‧‧‧O-ring 137a, 137b‧‧‧Leaf spring 200‧‧‧Moving mechanism C, C1, C2, C12, D, D1, D2, D12‧‧‧Spring cw‧‧‧Cooling water Da, Db‧‧‧Region Dm‧‧‧Maximum displacement P‧‧‧Critical value W‧‧‧Wafer

FIG. 1 is a diagram showing an example of a substrate processing device according to an embodiment of the present invention. FIG. 2 is a diagram showing an example of an edge ring and its peripheral structure according to an embodiment of the present invention. FIG. 3 (a) to (d) are three-dimensional views, top views, and cross-sectional views of an edge ring according to an embodiment of the present invention. FIG. 4 (a-1) to (a-2), (b-1) to (b-2) are diagrams showing an example of an edge ring moving up and down according to an embodiment of the present invention. FIG. 5 (a-1) to (a-2), (b-1) to (b-2) are diagrams showing an example of a contact member of an edge ring according to a first embodiment of an embodiment of the present invention. Fig. 6 (a-1) to (a-2), (b-1) to (b-2) are diagrams showing an example of a contact member of an edge ring according to a second embodiment of an embodiment of the present invention. Fig. 7 (a) to (b) are diagrams showing an example of a load change of a spring. Fig. 8 (a-1) to (a-2), (b-1) to (b-2) are diagrams for explaining the contact resistance of a contact member according to an embodiment of the present invention.

12‧‧‧Platform

16‧‧‧Conductive cylindrical support

16a‧‧‧Space

36‧‧‧Electrostatic chuck

37a, 37b‧‧‧Contact components

38i‧‧‧Inner edge ring

38m‧‧‧Central edge ring

38m1‧‧‧Annular part

38m2‧‧‧Protruding part

38o‧‧‧Outer edge ring

39i, 39o‧‧‧Heat transfer plate

100‧‧‧Shell

102‧‧‧Lifting pin

103‧‧‧Connection section

138‧‧‧Concave

W‧‧‧wafer

Claims (15)

A substrate processing device comprises: an inner edge ring disposed near a substrate placed on a platform in a processing chamber; a central edge ring disposed outside the inner edge ring and movable up and down by a lifting pin; an outer edge ring disposed outside the central edge ring; a first spring disposed between the inner edge ring and the central edge ring; and a second spring disposed between the inner edge ring and the central edge ring. A spring is disposed between the central edge ring and the outer edge ring, wherein the first spring maintains contact with both the inner edge ring and the central edge ring throughout the entire range of up and down movement of the central edge ring, and the second spring maintains contact with both the central edge ring and the outer edge ring throughout the entire range of up and down movement of the central edge ring. The substrate processing device as described in claim 1, wherein the first spring is disposed on a horizontal surface between the inner edge ring and the central edge ring, and the second spring is disposed on a horizontal surface between the central edge ring and the outer edge ring. A substrate processing device as described in claim 1 or 2, wherein the first spring and the second spring are arranged on the entire circumference. A substrate processing device as described in any one of claim 1 to 2, wherein the first spring and the second spring have the following characteristics: the load variation of the spring corresponding to the displacement is in an area below the critical value, and is above a specific ratio relative to the maximum displacement. A substrate processing device as described in any one of claim 1 to 2, wherein the first spring and the second spring are in the form of a coil. A substrate processing device as described in any one of claim 1 to 2, wherein the first spring and the second spring are in a tilted state. A substrate processing device as described in any one of claim 1 to 2, wherein the first spring and the second spring are formed of any one of benzene copper (BeCu), tungsten (W) or tantalum (Ta). The substrate processing device of claim 1 further includes a microcomputer for controlling the lifting pin to move the central edge ring by an amount according to the amount of wear of the central edge ring or an amount according to process conditions. The substrate processing device of claim 1, wherein the central edge ring has a first horizontal surface facing downward and a second horizontal surface facing upward, the first spring contacts one of the first horizontal surface and the second horizontal surface, and the second spring contacts the other of the first horizontal surface and the second horizontal surface. The substrate processing device of claim 1 further includes a cylindrical support portion, which is disposed on the outer side of the outer edge ring so that the top surface of the outer edge ring is flush with the top surface of the cylindrical support portion. The substrate processing device of claim 1 further comprises an electrostatic chuck, wherein the inner edge ring and the outer edge ring are fixed to the top surface of the electrostatic chuck via a first heat transfer plate and a second heat transfer plate, respectively. A substrate processing device as claimed in claim 1, wherein the outer edge ring has a portion overlapping with the top surface of the outer peripheral portion of the central edge ring. The substrate processing device of claim 1 further comprises: a piezoelectric actuator; a component connected to the component of the piezoelectric actuator; and a bearing portion connecting the component and the lifting pin; wherein the lifting pin is moved up and down by the power of the piezoelectric actuator through the component and the bearing portion. A substrate processing device comprises: an inner edge ring disposed near a substrate placed on a platform in a processing chamber; a central edge ring disposed outside the inner edge ring and movable up and down by a lifting pin; an outer edge ring disposed outside the central edge ring; a first spring disposed between the inner edge ring and the central edge ring; and a second spring disposed at the central edge ring. The central edge ring includes an annular portion surrounding the periphery of the substrate, and a plurality of convex portions arranged at equal intervals on the outer periphery of the annular portion, and the outer edge ring includes a plurality of recessed portions located on the bottom surface of the outer edge ring, the plurality of recessed portions are located above the plurality of convex portions and can respectively accommodate the plurality of convex portions. The substrate processing device of claim 14 further comprises a plurality of said lifting pins, wherein said plurality of protruding pieces are three protruding pieces arranged at equal intervals in the circumferential direction of said central edge ring, and said plurality of said lifting pins are three lifting pins arranged in a one-to-one correspondence with said three protruding pieces.